The_Working_Cell__5_

Phospholipid Bilayer

A structural component of cell membranes that consists of two layers of phospholipids.

Fluid Mosaic Model

Model describing the cell membrane as a flexible layer made of various proteins that float in or on the fluid lipid bilayer.

Selective permeability

The property of biological membranes that allows some substances to pass through while keeping others out.

Diffusion

The spontaneous spreading of molecules/ions from an area of higher concentration to an area of lower concentration.

Osmosis

The diffusion of water across a selectively permeable membrane.

Hypotonic

A solution with a lower concentration of solutes compared to the inside of a cell, leading to cell swelling.

Hypertonic

A solution with a higher concentration of solutes compared to the inside of a cell, leading to cell shrinking.

Turgor pressure

Pressure exerted by fluid in the central vacuole against the cell wall, keeping plant cells rigid.

Facilitated diffusion

Passive transport that assists the movement of molecules across the membrane via transport proteins.

Active transport

The process that moves ions or molecules against their concentration gradient using energy.

Endocytosis

The process by which cells take in large molecules by engulfing them, forming vesicles.

Exocytosis

The process of expelling materials from the cell by vesicles fusing with the plasma membrane.

Second Law of Thermodynamics

States that energy tends to disperse spontaneously, leading to increased entropy.

Metabolism

All chemical reactions in an organism used to gain and utilize energy.

Enzymes

Biological catalysts that speed up chemical reactions without being consumed.

Cofactors

Non-protein molecules that assist enzymes in catalyzing reactions.

Competitive inhibition

A form of enzyme inhibition where the inhibitor competes with substrate for the enzyme's active site.

Feedback inhibition

A regulatory mechanism where the product of a pathway inhibits an earlier step to regulate the pathway.